Yesterday I whipped up a skirt for Amelia. It is pretty much the same as my easy skirt tutorial. The only difference is the band is the smaller piece on this skirt and the shorter piece on the other skirt is the gathered part on the bottom. This skirt used a half metre of fabric which is about 20 inches. You could make a slightly shorter skirt with half a yard. This skirt fits my 5 1/2 year olds.
Fold the fabric in half. Cut a piece 20 inches across by 13 inches tall (when you fold it out it will be 40 inches wide). The cut a piece about 16 inches wide by 5.5 inches tall (so when you fold it out it will be 32 inches wide). You don't have to be exact with your measurements as the skirt is gathered and you cut the elastic to the size you want.
Now follow all the instructions in the tutorial here.